New codon codes for a different amino acid →change in primary structure of protein
Degenerate nature of genetic code : new codon may still code for the same amino acid leading
to no change in protein synthesised
, 2
Position & involvement of amino acid in R group interactions within protein determines
impact of new amino acid on function of protein
Eg. amino acids have role in active site = enzyme can’t act as a biological catalyst
● Deletion
● Insertion
Frameshift mutation
Triplet code (sequence of bases transcribed consecutively in non-overlapping groups of 3 =
reading frame of a sequence of bases)
Addition & deletion of nucleotide shifts reading frame = change every successive codon from
the point of mutation
N. nucleotides changed is multiple of 3 = reading frame not changed, but protein affected as
new amino acid added
Effects
No effect: normally functioning proteins still synthesised. In non-coding regions (introns) or
code for same amino acid
Damaging: phenotype affected negatively as protein not synthesised or non-functional
Beneficial: synthesised protein results in new useful characteristic in phenotype
Causes
Rate of mutation increased by mutagens (bio, physical or chemical agent)
Spontaneous depurination / depyrimidination → insertion of incorrect base through complementary
base pairing in DNA replication
Free radicals (oxidising agents) affect structures of nucleotides & disrupt base pairing
Antioxidants (anticarcinogens) negate effects of free radicals
★ Ionising radiation (eg. X-rays) break 1+ DNA strand
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller erikakumar. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $3.89. You're not tied to anything after your purchase.
